In eukaryotic cells the chromosome condensation occurs during mitosis or meiosis. However, the fusion of an interphase cell with a mitotic cell mediated by Sendai virus usually results in the condensation of interphase chromatin into prematurely condensed chromosomes (PCC) under the influence of factors present in the mitotic cells. We have recently observed that the mitotic factors from mammalian cells (HeLa) could induce meiotic maturation of amphibian oocytes which involves the breakdown of the germinal vesicle and chromosome condensation in the oocytes. This observation suggests that the factors involved in the breakdown of the nuclear membrand and chromosome condensation associated with mitosis, meiosis and PCC appear to be similar in all the animal species. The overall objective of this proposal is to purify and characterize the mitotic factors from HeLa cells using the meiotic maturation of amphibian oocytes as an assay system. The specific aims of this proposal are: (1) to isolate and purify the mitotic factors from the cytoplasmic and chromosomal extracts of mitotic HeLa cells; (2) to study the physical, chemical and enzymatic properties of the purified mitotic factors; (3) to investigate the biological activities of the purified factors both in the mammalian and amphibian oocyte system; (4) to study the relationship between protein phosphorylation and the activity of the mitotic factors; and (5) to characterize the heterologous antibodies that we have raised against the HeLa mitotic factors by injecting them into rabbits. The results of these studies could lead to a better understanding of the mechanisms involved in chromosome condensation and cell division in normal and malignant cells.